Swift vs Kotlin vs Flutter in App Development: What to Choose?

8 Dec 2021 | 19 min read
Flutter vs Kotlin vs Swift Comparison

Going mobile is the right direction for 2022 and onward, research suggests! So it’s only right that you’ve decided to invest in a mobile app of your own. But now some complicated questions may arise: should you insource or outsource, which platforms should you target, which programming language should you choose, etc. 

Previously, we wrote a comprehensive piece on how to choose the right type of app for your business, and today, we are talking about languages. In particular, three of the most in-demand languages for mobile application development these days: 

  • Kotlin (used for Android), 
  • Swift (designed for iOS programming),
  • and Flutter (bringing the best of both worlds through cross-platform development). 

But before we proceed with this ultimate mobile comparison, let’s quickly recall the main differences between native and cross-platform app development. 

Native vs cross-platform mobile app development

Native apps

As the name suggests, native applications are bound to the platform they’re designed for. As such, if you write Android apps, it will only function on that operating system. And if you eventually decide to scale up and target Apple devices, your development team will have to write a new code for scratch. 

This is why it’s paramount to know why you chose a certain operating system over another. Otherwise, you are risking your entire business. 

A good recent example of a native solution would be Clubhouse that was only available for iOS apps, leaving the rest of the people behind. A bold move, given that Android has over 70% of the global market share. However, if you are certain that your target audience is devoted to Apple, you get to significantly cut expenses and time to market with a native application. 

Cross-platform apps

Cross-platform, in turn, allows you to write code in such a way that the app you develop will look and feel exactly the same on both iOS and Android devices. Cross-platform development, powered by the Dart programming language, is the key to creating apps that seamlessly span across various operating systems. It is a perfect solution for businesses targeting general audiences or markets where both operating systems are equally represented. 

Cross-platform is a safer option, yet it is also more costly and time-consuming than native app development, which is why you need to know exactly what you hope to achieve with your application in the end. That’s where knowing the key differences between the most popular programming languages for mobile comes into play. 

Curious about cross-platform? Learn more about our cross-platform app development services and choose the right solution for your business!

Flutter vs Kotlin vs Swift: overview 

If you find yourself in a situation where choosing between native or cross-platform development won’t make much of a difference to your business profit-wise, it is wise to take a look at how demanding each technology could get. 

There’s no better way to do so than learning about the major advantages and disadvantages of the language your development team will be working on. 

Supported platforms and operating systems

SwiftKotlinFlutter
iOS

iPadOS

MacOS

WatchOS

tvOS

CarPlay
Android OS

Wear OS

Android TV

Android Auto

Kotlin Multiplatform

Server-side development

Desktop

Scripting

Web frontend development

Data science
iOS

Android

Web

macOS

Windows

Linux

Fuchsia

Custom embedded systems
Swift logo

iOS development with Swift

Swift is widely recognised as the best possible option for the Apple platform when it comes to quality and functionality. With this language, you can write a single code that will work across all the iOS devices (e.g. mobile, tablet, desktop, wearables, smart TV, etc.) without sacrificing any of the functionalities. 

Some of the popular apps using Swift are LinkedIn, Kickstarter, Eventbrite, and more.  

Kotlin logo

Android development with Kotlin

Since Google I/O 2017, Kotlin has been the main language for Android applications. Similarly to Swift it allows you to share the same code between different platforms (e.g. mobile apps, wearables, Android TV, or Android Auto). Apart from its wide native Android use, Kotlin can also be in server-side solutions and web application development services, making it an accessible cross-platform choice. 

Kotlin helped to build apps like Uber, Netflix, Pinterest, and Twitter. At Miquido, we used it to complete some of our coolest projects, like TUI or BNP Paribas applications. 

Flutter logo

Cross-platform development with Flutter

Flutter, on the other hand, is a 100% cross-platform framework dedicated to writing clean native-like code simultaneously for Android and iOS applications. Flutter supports a wide range of platforms while still relying on native code. Its versatility and speedy implementation make it the most popular among other cross-platform frameworks.

While Flutter is a very young framework, it’s already used by some of the world’s favourite brands, such as Google, Groupon, Philips, and more. Miquido has been among the first companies to adopt Flutter development solutions in its tech stack and relied on it to complete our crown jewel – the Topline app for the Abbey Road Studios. 

Pros and cons of each language for business owners and developers

Now that we’re done with the basics and you have a better understanding of what each language has to offer, it’s time to get more specific.

For those of you interested in the final outcome of your project, we made sure to include the business-oriented aspects of Kotlin, Swift, and Flutter. And for the tech whizzes out there, we also didn’t forget about the actual functionalities and specific features each language has to offer.

So buckle up! It’s time to choose the best language for your next digital product! 

The advantages and disadvantages of Swift

Advantages of SwiftDisadvantages of Swift
Apple OS features for all Apple platformsThe platform-specific code cannot be reused outside of the Apple ecosystem
Fast-forwarded access to App StoreHigh-quality specialists are rare to come by
Simplified code update upon new OS releaseLimited tooling and technical background from non-mobile domains
Support of structural, object-oriented, function, actor programmingEasy to learn at first but is very hard to master the specifics
High app performance and optimisation
Ongoing support from Apple

Swift is a strong alternative to Objective-C – the former crown king of iOS development. It comes with some fantastic business-oriented benefits:

  • Swift allows using the latest Apple OS features on Apple platforms (Apple actively promotes apps following their guidelines in ads, stores, and even during keynotes).
  • It supports platform-specific APIs andy system extensions which allows you to invest in one shared code for all the Apple-powered platforms you want to target at once while maintaining their native feel at the same time
  • Swift is also known to cause the least problems upon releases and app reviews.  This is a very important point to keep in mind since  Apple is very restrictive on app content, behaviour and API usage.
  • It is designed in such a way, that if a new OS update introduces any significant software changes, the Swift code can be easily adapted thanks to its high compatibility.
  • Compared to Objective-C and other native languages, Swift stands out with its immaculate app performance and optimisation when it comes to the launch time, resource usage (including battery) and the final size of app files.

As such, Swift is a convenient choice for pro-Apple digital solutions as it knows how to bypass the complex screening process and won’t fall victim to regular OS updates. 

Yet, let’s not get carried away, because we still have two other languages to review and Swift comes with its share of drawbacks as well: 

  • Swift relies on platform-specific code which cannot be easily reused outside of the Apple ecosystem (e.g. for Android and web solutions). This is why, if you know you’ll be targeting non-Apple users it’s best to choose another technology for your product.
  • Swift specialists need to rely on programming languages used almost exclusively for the Apple platform which causes them to be much less common than, let’s say, Java developers.
  • Due to its limited applicability, Swift doesn’t have strong tooling and technical background from domains other than mobile. It sometimes results in a lack of tooling equivalent to other languages or their worse quality. With the lack of good industry standards compared to more popular languages (such as Java) there may occur difficulties with large and/or complex applications. However, it doesn’t mean that you can’t make big and complex apps natively – you can, it is simply more demanding in some cases. 

Benefits and drawbacks of Kotlin

Advantages of KotlinDisadvantages of Kotlin
Interoperability with JavaHarder to learn when compared to Java
Clean minimal codeLess helpful for clean builds
Open-source community gitLess highly skilled developers available
Simple syntax familiar for Java, Python, or even Swift programmers
Helps developers avoid a lot of common bugs
A safer alternative to Java
Unique features such as asynchronous programming, scope and extension functions, string interpolation, etc.
Kotlin Multiplatform

When it comes to Kotlin, it is important to also mention Java – the old standard for Android (and other) mobile applications. So when we look at all the benefits of Java application development, it is important to highlight: 

  • Kotlin is interoperable with Java. It is consistent with Java and many other related frameworks and tools. This allows the developers to use Kotlin in Java projects and develop new features in Kotlin at the same time.
  • Kotlin can reduce the amount of code enormously, thus providing you with a cleaner project that is easier to read, understand, and take over if necessary.
  • Built and supported by JetBrains, the company behind the IDEs, such as Android Studio and IntelliJ, Kotlin is open-source, so the community has a big impact on new features and bug fixes.
  • Kotlin’s syntax is simple and even a beginner developer can grasp it relatively quickly. At the same time, the language offers sophisticated powerful features for experienced programmers, so that everyone gets their share of fun.
  • Kotlin helps developers avoid a lot of bugs that were very common in Java.
    The compiler can identify every possible mistake at compile-time without any hassle. The syntax takes care of reducing the number of possible errors(e.g. Elvis Operator). As a result, it turns Kotlin into a safer alternative to Java.

At the same time, there are certain things to look out for while choosing Kotlin as your programming language of choice: 

  • Even though Kotlin and Java share a number of similarities, they have some prominent differences as well. Kotlin has a lot of new features that don’t exist in Java, which makes it a harder but much more modern language.
  • Kotlin runs faster than Java in some cases, especially when doing incremental builds. But when it comes to clean builds, Java will always be faster. 

Flutter: the good and the bad

Advantages of FlutterDisadvantages of Flutter
Very fast time-to-marketNo support for Apple TV or Android TV
Wide platform support without additional costsLack of experienced senior developers
UI-oriented programmingOngoing dispute regarding good practices and state management
Strong support of the industry leaders (i.e. Google)Lack of dedicated libraries for certain native features
Simple architecture and ease of learningWeb support is still work in progress
Increased program stability thanks to Sound null-safety built into the languageServices are more expensive compared to native programming
Real-time changes in the code thanks to hot-reload
Very fast compilation

There are many great benefits of Flutter for businesses. Arguably, even more so than an alternative cross-platform framework would. However, it’s important to keep in mind that it’s still a very young framework that has its share of drawbacks and improvements. 

  • Flutter is known for its remarkably fast time-to-market abilities. Due to both intuitive code syntax and a pleasant work environment for developers, projects written with Flutter hit the stores faster. 
  • After its Flutter 2.0 update, the language now supports all the crucial platforms and operating systems without requiring any additional costs from the product owner. 
  • The industry leaders provide regular and in-depth backup for the language, which speaks both to its future potential and current quality of development.
  • Flutter is very easy to learn, which is why a company shouldn’t have a problem with retraining its current Android and iOS developers to use Flutter instead if such need shall arise. 
  • Flutter is packed with unique features, such as hot-reload with state persistence, which allows a developer to see changes in his code in real-time, without having to restart their app
  • Both App and Google Play Stores are known to treat Flutter-based apps kindly without any harsh pre-examination or extensive verification

When it comes to the disadvantages of entrusting your next product idea to a Flutter development team, most of them originate from the fact that the language has only been founded in 2012 and hasn’t had much time to evolve yet:

  • It is difficult to find senior Flutter developers simply because the programmers hadn’t had the chance to experiment with the language for a sufficient amount of time yet
  • As a rule, Flutter developers are more expensive than native developers because they need to be experts in more than one platform
  • Flutter has introduced web support, thus making itself a very comprehensive cross-platform language. However, its web-oriented toolset is still pretty limited and requires more work  
  • Many established languages, such as Java, thrive thanks to robust libraries available for any sort of request. Flutter does have its own community support and Google experts backing it up, however, its libraries are still nowhere near being complete

Final notes

As you can see, there are many factors you need to consider before deciding on a specific language for your next digital product. Far too many factors, perhaps. That’s why we advise our clients to trust the vendor with the solution. 

If you found this article complex and would need a more in-depth consultation regarding the best technology for your project, we’ll be happy to help!

Anna Kvasnevska Content marketing specialist

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